The Battle of the Atlantic was the dominating factor all through the war. Never for one moment could we forget that everything happening elsewhere, on land, at sea or in the air depended ultimately on its outcome.

Welchman, Gordon (1997) [1982], The Hut Six story: Breaking the Enigma codes, Cleobury Mortimer, England: M&M Baldwin, ISBN978-0-947712-34-1 New edition updated with an addendum consisting of a 1986 paper written by Welchman that corrects his misapprehensions in the 1982 edition.

Behrens, C.B.A. Merchant Shipping and the Demands of War London: HMSO)

Douglas, William A.B., Roger Sarty and Michael Whitby, No Higher Purpose: The Official Operational History of the Royal Canadian Navy in the Second World War, 1939–1943, Volume 2 Part 1, Vanwell Publishing 2002, ISBN 1-55125-061-6

Douglas, William A.B., Roger Sarty and Michael Whitby, A Blue Water Navy: The Official Operational History of the Royal Canadian Navy in the Second World War, 1943–1945, Volume 2 Part 2, Vanwell Publishing 2007, ISBN 1-55125-069-1

Morison, S.E. The Two Ocean War and History of United States Naval Operation in World War II in 15 Volumes. Volume I The Battle of the Atlantic and volume X The Atlantic Battle Won deal with the Battle of the Atlantic